Answer to Question #258460 in Physics for lawr

Question

If a car requires 30. seconds to accelerate from zero to 90. kph (km/hr), its average acceleration is, most nearly,

Answer 1

90 kph is

$$v=90·1000/3600=25\text{ m/s}.$$

The acceleration is the rate of change of velocity:

$$a=v/t=25/30=0.83\text{ m/s}^2.$$